Left 4 Dead Update Adds Custom Campaign Support

An update released today for Valve's zombie shooter Left 4 Dead allows users to easily download and play custom campaigns.

Content creators will now package their maps into a single .VPK file, which users can install with a simple double-click.
Players can manage their add-ons and campaigns within the game. Valve has also added matchmaking, leaderboards and auto-update/download support for custom maps.

Check below for the full patch notes:

Client

Removed an infinite ammo exploit for molotovs

The team swapping issue in Versus has been fixed

Add-on Campaign Support

Players download third party campaigns as single .VPK file

Players can manage and select add-on maps and campaigns via game UI

Added matchmaking support and download/update prompt for add-on campaigns